obticeō

1. Silere (from ἑλλός) means to be still, σιωπᾶν, in opp. to strepere, Suet. Aug. 94; whereas tacere (from tegere?) means to be silent, σιγᾶν, in opp. to loqui, dicere. And the compound word reticere, if a man has something to say, and keeps it to himself, in opp. to eloqui, proloqui; but obticere, if a man does not speak to one who asks or expects an explanation, in opp. to respondere. Cic. Harusp. 28. Sed tamen facile tacentibus cæteris reticuissem. 2. Tacens and tacitus denote being silent merely as a temporary state; tacens means any one who does not speak; tacitus, one who, when an opportunity for speaking offers, purposely refrains, and observes a significant silence; whereas taciturnus denotes silence as an habitual quality, like close and reserved. (i. 85.)